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Non Traditional Construction (Part 1)

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The Laing Easiform

The Laing Easiform

 

These were constructed by John Laing builders with the first house being built in 1919. They are a fairly common form of construction – they were built by Councils in large estates as they were fairly cheap and quick to build.

We have surveyed many Laing Easiforms in both Bristol and Gloucester. These dwellings can be identified by their tall slender chimney. The chimney tends to protrude from the central wall; however these chimneys often suffer from failure of the render and tend to crack. Laing Easiforms normally have a concrete porch roof above the front door. But the main way to confirm is by entering the loft space and looking at the party wall.This is not made of brick and block as in traditionally constructed houses, but is fairly smooth and grey in appearance.

How were they built?

Surveying these types of property can be a very satisfying experience as they were all constructed in a very similar way. A solid slab foundation was laid, then a mastic asphalt floor covering which acted as a damp proof course. After the floor was dry, metal shuttering was temporarily constructed and concrete was poured into this mould. This was strengthened with reinforcing bars. As these houses are not constructed from panels brought in from elsewhere, and the work is carried out on site, these are called in-situ. Once the concrete walls were in place, the shuttering was removed and the roof could be added. Normally a traditional cut-type roof was used with some bolted trusses to add strength, for instance those found in Brentry. A flat thick roof comprising a concrete slab was sometimes used, such as in Lockleaze.

What are the associated problems?

Laing Easiforms were not considered to be defective under the Housing Act and as a result can be mortgageable. Hence they are one of the few types of non traditional construction where a mortgage may be obtained! But With every rule there are the exceptions and the most common is the pre 1940’s Laing Easiform. Their construction had thinner walls, with 3” of poured in-situ concrete,  a 2” cavity and then a 3” inner skin – which is very thin by any standard. Some of these are still present in Lockleaze in Bristol and these are seldom mortgageable. The post-war properties were of  thicker walled construction, with  3 ½ ” concrete, a 2” cavity and a 3 ½” inner wall,  such as many of those found in Bishopsworth.

When we survey a Laing Easiform, one of the obvious problems is corrosion of the embedded metal. This is often characterised by horizontal cracking along the reinforcement lines. This may be repaired cost effectively depending on the extent of cracking that is apparent. It is a subjective call as to whether the extent of cracking is cost effective to repair; most suffer some level of cracking.

The other commonly occurring problem is the quantity of asbestos that is often used in the construction.For example, the soffits were originally of asbestos cement boarding, which has often been hidden by new UPVC. The loft hatches were again asbestos boarding, as were the under stairs cupboards. Many of the ducts and boxings-in were also cement type board and thermoplastic tiles were often used to finish the floor.

 

OH, GOOD, IT ALREADY HAS A NEW ROOF…

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roof

So you have diligently used our blog entries to guide you in viewing a property. You can see concrete tiles and the estate agent has said‘ Don’t worry,  it has a new roof!’ Why should you be concerned?!  Half of the ‘new roofs’ we inspect at in the Bristol area should have Building Regulations approvals and do not. Two aspects!  First, it’s difficult to sell a property without the correct approvals. Second,  the workmanship may not be acceptable if not approved.

As we know,pre 1950’s roofs in Bristol were usually covered with clay tiles (or slates) which were lighter than concrete.  Now it has a concrete roof  so we know from the planning portal that it is likely to need Building Control approvals.  This will ensure the roof structure is strong enough to support the concrete tiles. Also that Fire (Part B) and Energy Performance (Part L) criteria have also been met.

THE STRUCTURAL ISSUE

If it has been re-covered with concrete in the last say 5 years, then very little time will have elapsed. The building’s lifespan is a lot longer than ours!  And the faults linked with overloading the property’s roof structure can take years to develop. The existing timbers (the rafters and purlins) may be too thin to support the new heavier tiles. If they have been replaced, these may also be inadequate.

The replacement covering should have been constructed with input from a structural engineer. (S)He would have determined the loadings. He would then have checked that the load bearing walls were suitable for the increased loadings.

If the timbers have been replaced, they may have the stress gradings stamped on them. This shows the strength of the actual timbers.  C16 is weaker or C24 is stronger. The trada tables then give allowable spans depending on the centres.

Why does this matter? First the rafters will bow, causing the load(weight) of the roof to be sent at an angle into the walls. However, the load should besent vertically straight down to the foundations. This often leads to cracking around the tops of the walls, commonly known as roof spread.  This can be seriously expensive to repair.

Eventually the roof itself will deflect and the tiles become loose… look at the ridge line carefully!

 

WHY WOULD YOU SPEND SO MUCH MONEY AND NOT HAVE THE WORK APPROVED?

It is not normally the vendor’s fault! Roofing works are very expensive so it is likely that the cheaper quotes were accepted. From the roofing contractor’s  perspective,it does make life easier not to inform Building Control!  Awaiting Building Control inspections can delay payments and hold jobs up. And if the work is not inspected, the contractor would not be held liable for infringements at the time.

It is likely that this missing compliance “paper trail” is only identified when selling the house.It normally comes as quite a shock to the vendor!  Indemnities are often offered by the solicitor but thesemerely indemnify against enforcement action being taken by Planning or Building Control. They do not deal with the quality of the structure in any way.

HOW CAN YOU TELL?

There’s a very quick trade secret ! If the has been recently recovered and has less than 270mm of loft insulation present, then it would not comply and hence we know has most likely not been inspected. Otherwise, ask the vendor about the Building Control sign-off documentation. If that is not present, make sure your surveyor inspects the roof structure thoroughly, which won’t happen in a home-buyer’s report !

Pole Camera or Drone?

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IS IT A SELFIE STICK?

Members of the public and vendors often see us with cameras on tall poles at the front of houses.  It’s strange to see a fully grown man with a giant “Selfie Stick” as lots of people call them!They are intrigued by what we are doing and ask questions.

We have been using pole or mast cameras on every Building Survey we’ve carried out since 2012.You can see us using a 6m mast in this early video.  Over the years we have continued to refine and develop the mast camera.  Now  they can be up to 15m high, as can be seen in this incarnation from 2013.

Over this time, the cameras mounted on the 10m fibreglass poles used by all our surveyors have really come a long way. They now have tilting, panning heads to allow us to look behind parapet walls and in other hidden places.They are also much lighter and easier to handle for safety.

 

WHAT ABOUT BINOCULARS?

Strangely, the uptake of this technology by surveying firms in the UK has been very limited.  We pioneered the technique in Bristol!  We are still the only firm in Bristol offering this as standard in our Building Surveys -not as an added extra at a premium cost. The others tend to look from ground level with binoculars, which isn’t going to provide a comprehensive view. You will not be able to see the tops of chimneys, second storey flat roofs or behind parapet walls. Nor into the valley or butterfly roofs that are very common in Bedminster, Clifton, Easton and Totterdown .

WHY NOT A DRONE?

The main question we are asked is why don’t you use a drone? The answer is that we don’t need to use more complicated access technology to gain a similar view.

Most importantly, we need to view the sarking felt, which should lap into the gutters on a standard roof. This felt has often decayed just beneath the roof tiles; it is very rarely visible from ground level.  From taking the pole camera out of the car and setting it up, we can see this area within a few minutes.  Setting up a drone takes time.  Imagine manoeuvring it into place to hover right next to the tiles.  Getting the camera perched in the gutter looking upwards. This manoeuvre would require significanttime and skill.  And the potential for tile or gutter damage by the drone is a possibility!

The pole camera allows us to see the tops of chimney stacks and also the tops of parapet walls. It also shows other areas of complex roofs that we want to inspect in detail.  So why complicate the process by using a battery powered vehicle that cannot be used under certain conditions?Only the very expensive models can operate when there is high wind or excessive rain or in certain geographical areas.

 

THE POLE CAN GO WHERE DRONES CANNOT

This should be seen in the wider context of drone use. The current call for registering and licensing drone pilots would add another layer of cost and complexity. This is not warranted in the surveying of residential property. We would not be able to use of them near Bristol airportor sensitive sites such as the MoD. There are also the general privacy concerns. Our cameras only look at the house we are surveying, not at the back gardens of an entire street. Hence our camerasdon’t cause alarm to people sunbathing in what they though was the privacy of their back gardens!

The real skill lies not in taking the picture, but in being able to analyse what the picture means…

 

Gardens

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Gardens

Landscaping

An attractively landscaped garden is a great feature, but it requires maintenance, time and effort.  Is that decking going rotten? Is it dangerously slippery? Are there broken paving slabs or loose handrails to steps? Is there a pond that may be hazardous to small children?

Boundaries

First look at the size and shape of the garden; can you tell where the boundaries lie?  Does it seem regular and consistent with neighbouring gardens?  Often concrete posts are used to divide properties and demark the boundaries; see if these are visible. Is there access from a walkway or alley at the back or side of the property? How secure is the back gate?

Fences

Are the fences damaged? The cost of replacing a simple panel fence set in concrete in the ground is around £80/linear metre. Disposal of damaged material is extra. This may seem a simple DIY job but don’t overlook the cost of materials mounting up.Some sources suggest that a fence constructed to the British Standard (1722) should last around 15 years. However,careful treatment every couple of years will significantly extend the life.

You might try gently and discreetly leaning on the fence to test for movement!

Walls

Walls are constructed of many differing types of materials. They may be retaining significant amounts of soil, especially on terraced sites.  Hence,there should be holes to allow the soil to drain. Look for cracks or significant leans. Again like fences, the cost of disposing of a damaged wall is very time consuming, heavy and costly, before it is even rebuilt. We estimate £120 per square metre to simply rebuild a wall that is 9” or 220 mm in thickness, assuming that the foundations are acceptable and that does not include disposal of the old wall.

Plants

The words “Japanese Knotweed” strike fear into the heart of any home owner, let alone a purchaser. And this is becoming more common in Bristol and we are receiving more and more calls to confirm its identification. We have found it from Clifton to St George and St Pauls to Fishponds, to name a few areas. But it can be eradicated! So, if you see a plant you don’t recognise, Google images will help, but be wary of a quick identification as many plants look very similar. Some web sites do offer free identification from photographs, but often they do not respond if they are busy so don’t expect too much for free.

Trees and Hedges

Again trees can cause concerns for even the most experienced purchaser. If you are viewing in winter, remember that full summer foliage will shut out daylight. Leaf falls from nearby trees block gutters and drains. Tree roots can damage the foundations and drains, causing subsidence issues.  Such roots can lift paving, too.  Remember the rule of thumb that the height of the tree is often the spread of the roots.

is the tree a particularly large or a striking specimen,if so ask the vendor if there are any Tree Preservation Orders in place. If so, even basic maintenance will need planning permission!

And those high, thick hedges will require cutting regularly in the growing season, as well as draining all the moisture from the adjacent flower beds.

 

Ceilings

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Ceilings

Ceilings are made from a variety of materials and each has different associated problems!

Did you read our blog on inspecting lofts and venture into the loft space (wearing a PP3 mask)? If so, you might be able to lift the insulation and see the type of ceiling material below.

Lath & plaster

Lath & plaster ceilings were used extensively pre 1940. They comprise wooden laths coated with various layers and thicknesses of plaster.  The plaster may contain ash, horse hair and lime.

While working for many leading insurance companies, we have inspected countless collapsed lath& plaster type ceilings.Lath & plaster can and will eventually fail. It happens in the most expensive houses which have decorative cornices that run into thousands of pounds to replace in a single room. It also happens in pre 1930 council houses.  Famously, the ceiling collapse at the Apollo Theatre in London in 2013 injured over 70 people. Such ceilings are seldom used now except in restoration work in listed buildings.

These ceilings are very thick,  normally around 20mm. The tell-tale signs of failure are cracking, an undulating surface and sagging. Finishes such as lining paper tend to mask such cracks but the undulations are easy to see.   Sagging suggests that the plaster has detached from the wooden laths above.  The cracking is not inregular, straight lines -it is normally diagonal and irregular.

Removing such ceilings is a very dirty job!  And it is a real challenge to save any ornate cornices running around the perimeter of the room. This dusty job is often expensive as few want to undertake this work.

Sometimes you can deal with lath & plaster ceilings by underboarding them. Underboarding is screwing a layer of plasterboard beneath the lath & plaster to support it. This is an inexpensive repair but will lower the ceiling height and you will lose any cornicing.

Hardboard

Occasionally in the 1950’s and 60’s, ceilings were constructed from thin sheets of hardboard, ie reconstituted timber. It is normally fairly easy to spot these from underneath, as they have tape over the joints of the boards. This gives the ceiling a grid like type of pattern!

Plasterboard

Since the 1940’s, ceilings have been constructed of uniform boards of gypsum known as plasterboard. These boards have a long service life.In the early days, when plasterboard was first used, the joints were not taped with a netting scrim. Hence minor thermal movements and stress cause straight line cracking, sometimes at right angles.  When this is the case, the joints can be taped  over and the ceiling skimmed. Sometimes nail pops are evident. As long as these are repaired properly (not just covered in filler) they are unlikely to re-appear.

Polystyrene tiles

These were most popular in the 1970’s. They were often used to disguise cracking or damaged ceilings. However, they are a fire hazard as they were not intumescent .  If they catch fire, they can rain molten polystyrene,  a scary image! These should be removed as soon as practicable. While removing the tiles is fairly easy, the plaster beneath will probably be damaged as a result. The spots of glue are also very hard to remove. So allow costs for the skimming often required after removal.

Timber cladding

Timber cladding was another old favourite. These are strips of tongue-and-groove wood and hence are flammable. So they can pose a risk, especially if they are used in a Kitchen. The cladding is not fixed direct to the ceiling; it is often nailed to timber battens which are screwed through the ceiling.  Removing  these will disrupting the finish beneath. Hence you should only undertake this if you are willing to plasterboard and skim the ceiling beneath.

Artex

Artex has been used since the 1970’s, an applied finish with various patterns from stipple to swirl. It was sometimes used on plasterboard instead of a skim, so the characteristic straight line cracks, often with right angles, are very common. Patching Artex satisfactorily  is very difficult and the repairs always seem to be obvious.  Hence when a section is damaged, it is often better to simply skim over the entire ceiling.  However, Artex applied prior to 2000 can sometimes contain traces of asbestos so scraping off the more pointy bits can be hazardous. If such ceilings appear damaged, then it is always best to have tested  it prior to purchase, because  removal of a medium size asbestos-containing ceiling costs around £800.00. And you will still have to replace the ceiling!

Windows and Doors

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domestic surveys

Windows and Doors

Windows form a large part of a building and give much of its character! They let in light but they are vulnerable to breakage, accidentally or deliberately. They can usually be opened for fresh air but  can be a security risk. Hence they need to be lockable with a key, to be “approved” by insurance companies. They can also allow heat to escape from the building.

On a viewing, you can easily see whether window locks are present . Again, doors need to be provided with locks that are approved to a BS standard.

Window Frames

The simplest test to tell whether  new frames are required?  Open and close the windows in every room whilst you are viewing. This will take minutes to perform but will indicate the likelihood of a bill for replacement – from £400 per window depending on the size. Yes, even on newer builds – as one minute into this video of our surveys in Bradley Stoke shows! https://youtu.be/1FENY2nJ24Y

There are many shapes and sizes of window, in a variety of materials. Genuine Georgian windows had small panes because glass was difficult to make. The Victorians found new methods of firing glass and so large panes, often in sash windows, became fashionable.

Wooden Frames

Into the 1960s, window frames were made of wood.Older timber frames do offer good thermal performance and can give a long service life, assuming careful maintenance has been carried out. However, they are prone to decay. Sometimes decay is visible as rotting wood. Sometimes fillers have been used. Don’t be afraid of gently prodding, to test the timbers. The filler often looks smoother than the surrounding timber.

Metal Frames

In the 1960’s, steel window frames were sometimes installed, often known as Crittall after the manufacturer. These are normally single glazed with very thin frames. Use a magnet to tell if the frames are steel.  These frames perform very badly thermally and normally have a good coating of mould to show that. These should be replaced.

Aluminium frames were used in the 1980’s. These are lightweight and do not rust. They may have a small brown-coloured layer sandwiched in their construction.  This acts as a thermal break to prevent condensation. If this is not present, replacement is certainly necessary.

As this older double glazing was a lot thinner,  replacement is normally required anyway as it is not feasible to upgrade the glass.

UPVC Frames

The early forms of UPVC were often single chamber or extruded solid plastic,hence  older UPVC windows often do not perform well thermally. Newer UPVC windows have multiple extruded chambers. These act as thermal pockets to make sure that they insulate the interior from the outside world. Combined with e-coatings, this gives one of the best performing arrangements available for the cost.The viable life of UPVC window frames is generally reckoned as 25 years.

Since 2002, new window installations should be “self-certified” by FENSA or CERTAS or in some instances Building Control will sign them off.

Ask the vendor or agent when the windows were last replaced.  Are there any guarantees? If 2003 or later, ask if the relevant certifying  documentation is present.

Glass

Single glazing is simply a single pane of glass.If this is the case, it usually indicates considerable age of a window installation. They allow a large amount of heat to leave the building and sums for replacing them should be budgeted. The reduction in heating bills should eventually pay for this alone!  Large panes of glass can also be dangerous if unmarked.

Depending on the age of the installation, double glazing may be e-coated and toughened.  We use some very special laser equipment to determine if this is the case,as can be seen on this link https://youtu.be/3fsDmGnaJjY . You will not be able to do this yourself, so look for the basics. Is there moisture (often looking like raindrops) in between the double glazed panes? If so, the seal to the double glazing has blown. These can seldom be repaired effectively and replacement is then required. This seal failure can often be as a result of pressure from the masonry, so look around these areas for cracks or distortion of the walls.

Doors

Again, doors may be timber, metal or UPVC, with or without glazed panes. The frames can warp, the locks can be ineffective. The hinges can sag. Replacement UPVC doors can cost upwards of £500, much more for French doors or bi-fold doors.  So do make sure you check them by opening and closing them.

While antique glass in doors, particularly entrances and hallways, is very attractive, it can be a safety hazard. It is unlikely to be toughened so is easily damaged by impact. If you have small children, do bear this in mind!

 

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